The present invention relates generally to agricultural equipment, and more particularly to a disc blade for tilling soil. The disc blade of the present invention may be used with harrows or similar equipment and is suitable, for example, in vertical tillage applications.
Disc blades have been used in the agricultural industry to work soil, i.e., leveling, breaking up, burying residue, etc. Disc blades may typically be attached to, or operate as part of, devices such as a harrow or similar agricultural implements. The disc blades are pulled through the soil while being caused to rotate. The rotating blade engages the soil as it passes through the soil, thereby working the soil. This may be done, for example, in preparation for planting and/or for seasonal soil maintenance.
Prior art disc blades have been made in numerous configurations. However, nearly all such prior art blades typically have a generally round (disc-like) shape with either a generally flat or a generally concave central portion configured with a hole or other opening, or openings, configured to mount the blade to a harrow or similar agricultural implement. Many of the other features of such blades can vary depending on the nature of the particular tilling application and the characteristics of the soil being tilled, such as the hardness of the soil, the presence of rocks or other content, and/or the presence of certain types of agricultural residue.
For example, some prior art blades have a generally smooth surface. However, other blades have been formed with surface deformations, such as flutes, ridges, grooves, scallops, waves and the like that are designed to cut and move the soil in a manner that results in the desired soil condition.
Similarly, some other prior art disc blades include a generally circular edge (or perimeter or periphery), while other disc blades incorporate various edge geometries and/or deformations, such as notches, grooves, bevels, teeth, saw-teeth and like structures that are adapted to address various types of soils and tilling conditions.
Prior art disc blades have been made in various diameters, ranging from diameters of about 8 inches to diameters of about 36 inches, depending on the geometry and configuration of the particular blade, the nature of the particular tilling application and the characteristics of the soil being tilled. Similarly, prior art disc blades have been made either as flat disc blades (having essentially zero concavity), shallow concavity blades (having radii of curvature in the range of about 850-1000 mm) or as high concavity disc blades (having radii of curvature in the range of about 600-750 mm). In this context, the radius of curvature of the disc blade refers to degree of curvature of the curved portion of the disc blade.
One particular disc blade that has been developed in the art is a disc blade with a radially toothed cutting edge or outer periphery, i.e., the edge comprises teeth having a generally radially sinusoidal, or wavy, geometry. This prior art disc blade includes a generally circular plate having a peripheral radially toothed cutting edge, a smooth (i.e., non-fluted, non-wavy) central portion configured to mountingly engage a harrow or like agricultural implement, and a wavy (or fluted) portion having a plurality of waves or flutes formed by a plurality of adjacent crests and valleys disposed between the smooth central portion and the radially toothed edge.
In this particular prior art disc blade, the plurality of crests, as viewed from one side of the disc blade, extend radially from the central portion of the disc blade at a distance that is further than the distance that the plurality of valleys. In this manner, a radially toothed cutting edge is formed along the outer periphery of the blade. The geometry of this radially toothed edge may provide for improved soil and residue cutting performance while at the same time providing the disc blade with the ability to self-sharpen with ongoing use. The toothed cutting edge includes a plurality of teeth that are symmetrically formed.
That is, as the disc blade wears with use, and the diameter of the disc blade decreases, the structure of the disc blade provides that the crests and valleys will wear generally evenly, maintaining the radially toothed profile of the outer periphery of the disc blade instead of wearing unevenly and creating a generally smooth outer periphery over a period of extended use. Thus, with wear, the edge of the disc blade will generally maintain its radially toothed profile instead of becoming smooth (non-toothed), as has been the case with other prior art disc blade designs.
In the traditional disc blades, the number and depth the of waves (i.e., the crests and valleys) may vary depending on the diameter of the disc blade, the nature of the particular tilling application and the characteristics of the soil being tilled (such as the hardness of the soil, the presence of rocks or other content, and/or the presence of certain types of agricultural residue). For example, a common 20 inch blade may have 32 waves formed by the plurality of adjacent crests and valleys, and each wave may have a depth of between 6 and 9 mm (this distance from the top of one crest to the bottom of an adjacent valley). However, numerous variations in the number of waves and their depth are possible.
Traditionally, tilling has been accomplished using horizontal tillage methods and apparatuses as are well known to those skilled in the art. In recent years, however, the agricultural industry has embraced a relatively new type of tilling known as vertical tillage. Vertical tillage involves the use of disc blades configured in a generally vertical orientation relative to the soil. That is, the blades are mounted such that the edge or outer periphery of the blade is perpendicular or transverse to the horizontal plane of the soil, such that the disc blades may cut vertically into the soil. Those skilled in the art are well versed in the advantages of vertical tillage over horizontal tillage, however, one of the major advantages of vertical tillage is the ability to cut, size and bury residue.
Because vertical tillage applications involve relatively high speed and relatively shallow depth use of disc blade, as compared to horizontal tillage applications, prior art disc blades designed for use in prior art horizontal tillage applications are not suitable for use in vertical tillage systems. That is, many such prior art disc blade designs would create undesirable side effects if used in vertical tillage applications, such as unacceptable soil throw. Additionally, many prior art disc blade designs do not have a sufficiently sharp edge for cutting, sizing and burying residue. Further still, symmetrically formed teeth formed along an edge of the disc blade may provide an inadequate tilling function.
What is needed, therefore, is a new disc blade that is particularly suitable for use in vertical tillage applications. Preferably, such a disc blade comprises a wavy disc blade with a radially toothed edge or outer periphery configured to improved cutting, sizing and burying of residue. The present invention satisfies this need.